Control system



W. G. COOK CONTROL SYSTEM April 8, 1930.

Filed Sept. 15, 1928 INVENTOR Wa la/"d 6i 5 00/?1 Q ATTORNEY PatentedApr; 8, 1930 UNITED STATES PATENT orrlce WILLARD G. COOK, OFPHILADELPHIA, PENNSYLVANIA ASSIGNOR TO WESTING- nousn ELECTRIC VANIA 8aMANUFACTURING COMPANY, A CORPORATION OF PENNSYL- GONTROL SYSTEMApplication filed September 13,-1928. Serial No. 305,755.

My invention relates generally to relays, and more particular to timeelement relays. In the design an construction of relays, it is Oftendesirable to provide for a long time'element delay in the operation ofthe device. Heretofore the time element has been too short for a greatmany purposes and other expedients have been resorted to.

The object of the invention generally stated, is the provision of a timelimit relay be obvious and will, in part, appear hereinafter.

The invention accordingly'is disclosed in the embodiment thereof shownin the accompanying drawing and comprises the features of construction,combination of elements and arrangement of parts, which will beexemplified in the construction hereinafterset forth and the scope ofthe application of which will be indicated in the claims.

.For a fuller understanding of the nature and objects of the invention,reference may be had to the following detailed description taken inconjunction WllI-ll. the accompanying drawing, in which:

- Figure 1 is a view inside elevation of a relay constructed inaccordance with this invention;

Fig. 2 is a front elevational view of the relay illustrated in Fig. 1;

Fig. 3 is a diagram illustrating how the relay may be connected into acircuit;

Fig. 4 shows a number of curves which demonstrate the characteristicspossessed by a relay constructed in accordance with this invention, ascompared with other types of relays;

5 is a perspective view of a portion of.

the relay mounted.

Referring now to the drawing, the relay illustrated comprises a frame10, in which a core member 11 is mounted. The 'core showing] how thearmature is member may be mounted in any suitable manner and in thisparticular showing, one end is threaded to engage in a threaded opening12 provided in the base of the frame 10. Extending substantiallyparallel to the core member 11 is a support 13 which, in this instance,is formed integral with the base of the frame 10. I r

An armature 14 is mounted on the support 13 and disposed in alignmentwith the core member 11. In order to mount the armature foroscillatorly. movement, a notch may be provided at t 1e end of thesupporting member 13. In the'construction illustrated, av notch 16 isprovided by mounting on the support 13, a plate15 which extends a shortdistance beyond the end of the latter.

, The simplest type of armature that is suitable for this relay is ametal plate which is cut with a square end.- In order to provide foroscillatory movement of the armature when mounted in the notch 16,provided between the end of the support13 'andthe plate 15, it isnecessary to space the walls defining the notch at an angle greater thana right angle. In this embodiment of the invention, in order to make thenotch of the required angular extent, the plate 15 is bent upwardly at apoint near the upper end of the support 13.

It will be readily understood that a sufficient angular movement of thearmature may be obtained if the angle of the notch 16 is only slightlygreater than the angle of the upper corner or knife edge 17 of the endof the armature 14 which seats in the notch. In

practice, it has been found that it is suliicient to make the notch ofan angular extent of from 5 to 7 greater than a right angle.

In order to mount the armature 14 so that it may be readily removed andreplaced, a rectangular notch 18 is cut in the laterally extending plate15. In cutting the notch, the plate is cut at two places to form atongue 19 which is bent upwardly at an angle of about 45. As shown, aplate 20 is mounted on the armature and provided with an extension ortongue 21 which extends through the notch 18.

The upper tongue 19 which is integral with vplate is provided with aslot 22 extending inwardly from the end for receiving a bolt 23, whilethe tongue 21 has an opening through which: the bolt extends. A spring25 is mounted on the bolt 23 and is disposed to bias the armature 14counterclockwise about the knife edge 17. In this manner, the armatureis retained in position, the tongue 21 engaging thesides of the notch 18to prevent lateral movement, while the spring 25 biases it upwardly inthe notch 16.

The armature may be readily removed by compressing the spring andforcing the bolt upwardly to permit the moving of thearmatur'e laterallyand the sliding of the bolt out v of the slot 22.

adjustable nut 26 whereby any desired spring As shown, the bolt 23' isprovided with "an;

receiving face 30. In this construction, the armature engages directlyw1th the face 30.

In order to actuate the armature 14, a main magnetizing coil 31 ismounted on the core 1 member 11. As will be readily understood, thiscoil may be made from any desired number of turns of suitable conductorwhich will depend on the operating conditions to be met.

As shown, a neutralizing coil 32 is mounted on the core 11 and may beconnected to oppose the magnetizing action of the main coil 31. The sizeof the conductor and the number of turns provided in the coil32 willdepend upon the main actuating coil 31 and the manner in which it isdesired to dissipate the residual magnetism that may be retained by thecore 11 during the operation of the relay.

In the operationof the relay, the armature 14 may be actuated to theposition illustrated, by the spring 25 only when the strength of thedecaying fluxbecomes less than the bias? ing force of the spring.Generally, it is desirable to reduce the strength of the spring to theminimum required in order to obtain fine adjustments as to time.However, such adjustments are difficult, to make unless there is afairly rapid or appreciable and continuous decay of lines of flux inthe-magnetic circuit under which conditions, if the spring is properlyadjusted, the actuation of the armature will occur promptlyand at apredegermined instant depending upon the biasing orce.

It will be readily understood that when a neutralizing coil 32 isprovided, that after the energizing circuit of the mainmagnetizing coil31 is interrupted, that the linkages tending to hold the armature 14 incontact with the face 30 of the core 11 may be substantially dissipated,permitting the actuation of the armature counterclockwise as viewed inFig. 1 by a very light spring. In the structure shown, when the armature14 is actuated counter-clockwise, the plate 20 mounted on the armature14 is moved into engagement with the set screw 29. 7

Referring now to Fig. 3, a circuit is illustrated showing how the relaymay be connected into a circuit. It will be observed that theneutralizing coil 32 is connected directly across the line conductors 33and 34 and is continuously energized. The main actuating coil 31 is alsoconnected across the line conductors 33 and 34 but has a circuit breaker35 or other suitable switching means connected in series therewith. Inorder to provide for dissipating energy when the circuit is interrupted,a resistor 36 is connected in parallel with the actuating coil 31. a v

In this particular circuit, the load 37 is connected-across the line inparallel with the coils 31 and 32. The contact members of the relaywhich are the armature 14 and the terminal 29, are shown connecteddirectly in the load circuit, but it will be readily understood that inpractice, they would probably be used to control an electromagneticswitch (not shown) which would, in turn, control the load clrcult. Inorder to explain the functioning and opoperation of the relay, referencewill be made to the curves shown in Fig. 4 which illustrate theperformance of the rela when provided with an air gap shim, wit out ashim and finally with asuitabl'e neutralizing coil. The curves wereplotted with flux densities as ordinates and time intervals asabscissae. I

It'will be noted that no shim is provided in this construction. However,the advantages of the present construction cannot readily be appreciatedwithout making a comparigap shim, the flux decayed very rapidly upon theinterruption of the magnetizing circuit through the main actuating coil31, as shown by curve 38. As will be readily understood;

the desired operation of the relay cannot be obtained with any certaintyat a point beyond the knee of the curve which is substantially indicatedby the ordinate 39. v

When the air gap shim, was removed and the relay tested, a curve similarto was obtained which indicates that the flux decayed more gradually,but the residual magnetism p was much greater.' In this instance, thesame spring tension will not effect the operation of the armature. Theknee of the curve is substantially-the ordinate 41. While the relaywithout the air gap shim gives a greater time interval, yet the springpressure required to actuate the relay is excessively high and unsuitedfor continuous operation.

The relay when equipped with a neutralizing coil such as 32, gave acurve 42 in which the knee of the curve indicated bythe point '43, isfound to be much further along the abscissa and the residual magnetismis reduced to substantially zero. This shows that 7 the time element isconsiderably increased.

In carrying out the test, the selected relay was operated under similarconditions as to spring pressure and voltage. The time intervalsindicated by thepoints 39, 41 and 43, were .52,1.05 and 1.7 seconds,respectively.

From the above, it will be readily understood that the relay providedwith a neutralizin coil gives a much more gradual decay of ux, therebyincreasing the time interval during which positive operation of therelay at a predetermined time may be obtained by the setting of thespring 25. Further, since the residual magnetism is reduced tosubstantially zero, there is no possibility of the armature sticking,since the linkages are substantially all dissipated and the armature maybe actuated by a comparatively weak spring.

Since certain changes may-be made in the above construction anddiflerent embodiments of the invention may be made without departingfrom the scope thereof, it is intended that all matter contained in theabove description or shown in the accompanying drawing shall beinterpreted ,as illustrative andnot in a limiting sense.

I claim as my invention:

1. In a relay in combination, a core member, an adjustable spring-biasedarmature disposed in alignment with the core member, a main coil formagnetizing the core member to efiect the operation-of the armature, anauxiliary coil disposed to dissipate the residual' magnetism in the coremember when the main coil is deenergized, thereby to increase thetimeduring which the magnetism of the core dissipates at a rapid rateand the period of time during which positive functioning of the armaturemay be obtained at any predetermined time interval.

2. In a relay in combination, a movably mounted armature, means forbiasing the armature to predetermined positions, an electromagnet fromwhich when deenergized the lines of magnetic force dissipate rapidlyuntil substantially only the lines of magnetic .force constituting theresidual magnetism remain, said electromagnet being disposed to actuatethe armature, an auxiliary coil associated with the electromagnet anddisosed to dissipate the residual magnetism when the electromagnet isdeenergized togive a continuous and rapid decay of the flux to permitthe operation of the armature under the influence of the biasing means.

3. In a relay in combination, a movably mounted armature, means forbiasing the armature to a predetermined position, an electromagnet fromwhich the-lines of magneticforce dissipate rapidly until substantiallyonly the lines of magnetism constituting the residual magnetism remainwhen deenergized, said electromagnet being disposed to actuate thearmature, an auxiliary coil for dissipating the residual magnetism ofthe electromagnet to increase the time during which lines of magneticforce are dissipated from the electromagnet with suflicient rapidity topermit the operation of the armature at any instant during the processof dissipation of flux, thereby to increase the time during which thepositive functioning of the armature may be obtained in response totheblasing force of said biasing means. 4. In a relay 1n combination, aframe, a

core member provided with an armature receiving face carried by theframe, an armature supporting member mounted on the frame, an armaturedisposed in alignment with the core member carried by the supportingmember, said supporting member being provided with a notch for receivingan end of the armature, the end of the armature disposed in the notchbeing provided with a knife edge, the angular extent of the end of thearmature about the knife edge being less than the angular spacing of thewalls of the notch, thereby to permit oscillatory movement of thearmature in the notch, means for biasing the armature to a predetermined,position, said biasing means being disposed to retain the armature inposition in the notch, a main energizingcoil mounted upon thedeenergization of the electromagnet thereby to permit the positive andprompt operation of the armature at a predetermined instant dependingupon the adjustment of the biasing means.

6. In a relay, in combination, a movably mounted armature, adjustablespring means for biasing the armature to a predetermined position, anelectromagnet disposed to generate flux for actuating the armatureagainst the action of the biasing means, an auxiliary coil associated'with the electromagnet for dissi ating the flux rapidly andcontinuously to su stantially zero upon the deenergization of theelectromagnet thereby to permit the positive and prompt operation of thearmature at a predetermined instant depending upon the adjustment of thebiasing means. 7. In a relay, in combination, a core member, a springbiased armature in alignment with the core member, means for varying thebiasing force applied to the armature, a main coil for magnetizing thecore member to .efi'ect thevoperation of the armature, an auxiliary coildisposed to eifect a substantially constant dissipation of the residualmagnetism of the corefrom the maximum energized condition to zero,thereby to obtain a prompt action of the armature at any predeterminedtime during the process of the dissipation of the residual magnetism inresponse to adjustments of the means for varying the biasing forceapplied to the armature.

8. In a relay, in combination,- a core, member, a spring biased armaturedisposed in alignment with the core member, a spring for biasing thearmature to a predetermined position, means for varying the biasingforce of thesprin a main coil for magnetizing I the coil mem er toeffect the operation of the armature, an auxiliary coil disposed toeffect a substantially constant dissipation of the residual magnetism ofthe core from the maximum energized condition to zero, thereby to obtaina prompt action of the armature at any predetermined time during theprocess of dissipation of the residual magnetism, in response toadjustments of the means for varying the biasing force of the springthat is applied to the armaturel i In testimony whereof, I have hereuntosubsciibed my name this first day of September, 19 8.

G. COOK.

